In a plant for mass mechanical shelling of nuts having a cracker, sheller, and air separators, this process bypasses the sheller with some cracked nuts. Nuts and nut parts created in the cracker are sent to bypass structure where in successive operations, the nuts are separated by width then by thickness. Those nuts having the largest width are shelled by parallel rubber coated cylinders. The remaining nut parts having smaller thickness/width ratios bypass the sheller of the prior art. Parts having larger thickness/width ratios are sent to the sheller of the prior art. The process is performed by screens which separate the cracked nut parts by width. For each width of nut parts, slots between revolving cylinders, separate the larger thickness parts from the smaller thickness parts.